Gimsa Jan, Radai Michal M
Department of Biophysics, University of Rostock, Gertrudenstr. 11A, 18057 Rostock, Germany.
Independent Researcher, HaPrachim 19, Ra'anana 4339963, Israel.
Micromachines (Basel). 2023 Mar 17;14(3):670. doi: 10.3390/mi14030670.
The DEP force is usually calculated from the object's point of view using the interaction of the object's induced dipole moment with the inducing field. Recently, we described the DEP behavior of high- and low-conductive 200-µm 2D spheres in a square 1 × 1-mm chamber with a plane-versus-pointed electrode configuration from the system's point of view. Here we extend our previous considerations to the plane-versus-plane and pointed-versus-pointed electrode configurations. The trajectories of the sphere center and the corresponding DEP forces were calculated from the gradient of the system's overall energy dissipation for given starting points. The dissipation's dependence on the sphere's position in the chamber is described by the numerical "conductance field", which is the DC equivalent of the capacitive charge-work field. While the plane-versus-plane electrode configuration is field-gradient free without an object, the presence of the highly or low-conductive spheres generates structures in the conductance fields, which result in very similar DEP trajectories. For both electrode configurations, the model describes trajectories with multiple endpoints, watersheds, and saddle points, very high attractive and repulsive forces in front of pointed electrodes, and the effect of mirror charges. Because the model accounts for inhomogeneous objectpolarization by inhomogeneous external fields, the approach allows the modeling of the complicated interplay of attractive and repulsive forces near electrode surfaces and chamber edges. Non-reversible DEP forces or asymmetric magnitudes for the highly and low-conductive spheres in large areas of the chamber indicate the presence of higher-order moments, mirror charges, etc.
介电泳力通常从物体的角度出发，利用物体的感应偶极矩与感应场的相互作用来计算。最近，我们从系统的角度描述了高导电性和低导电性的200微米二维球体在一个1×1毫米的方形腔室中，采用平面与点电极配置时的介电泳行为。在这里，我们将之前的考虑扩展到平面与平面以及点与点电极配置。球体中心的轨迹和相应的介电泳力是根据给定起始点处系统总能量耗散的梯度计算得出的。耗散对球体在腔室内位置的依赖性由数值“电导场”描述，它是电容性电荷 - 功场的直流等效物。虽然平面与平面电极配置在没有物体时没有场梯度，但高导电性或低导电性球体的存在会在电导场中产生结构，从而导致非常相似的介电泳轨迹。对于这两种电极配置，该模型描述了具有多个端点、分水岭和鞍点的轨迹，在点电极前方有非常高的吸引力和排斥力，以及镜像电荷的影响。由于该模型考虑了不均匀外部场引起的物体不均匀极化，这种方法允许对电极表面和腔室边缘附近吸引力和排斥力的复杂相互作用进行建模。腔室大面积中高导电性和低导电性球体的不可逆介电泳力或不对称大小表明存在高阶矩、镜像电荷等。
